You can also restrict access to any combination of Number section, Billing & payments section, Product search tools sections and Settings when adding a new user from https://dashboard.nexmo.com/users.

Other features include:

Edit and delete users

Add company name and description

Assign user to an API key

If you assign a user to an API key or multiple API keys they will only be able to manage or view the usage, search tools and settings for those API keys. This is useful if you wish grant access for certain individuals to specific API keys.

By default your account is enabled with a single Master API key and secret, you can request more by contacting support@nexmo.com.